Disposition of aquifer system in parts of Gadilam, Paravanar, Lower Vellar Watershed, Cuddalore district, Tamil Nadu

The distribution and quantification of ground water in the aquifer system is prime importance for efficient management of groundwater. Aquifer mapping studies bring out the vertical and lateral extent of the aquifer system which in turn paves way for efficient management of the aquifer system. Such studies were carried out in the Part of Gadilam – Paravanar watershed of Cuddalore district to bring out the aquifer disposition. The study area (Part of Gadilam -Paravanar watershed) lies between North latitudes 11° 25’ 23’ and 11° 45’ 36” and East longitudes 79° 28’ 23” and 79° 47’ 15”and falls in survey of India Toposheet No.58 M/6, 58 M/10 & M/14 AND 58 m/11. The total extent of the study area is 990 Sq. Km. The area experiences tropical humid climate with an average annual rainfall of 1400 mm which is received during both southwest and northeast monsoons. The area is drained by Paravanar and Uppanar rivers. Geologically the area has three distinct formations: Recent Alluvium, Cuddalore sandstone of Mio-Pliocene age and Sandstones of Eocene age.

The data obtained from the exploratory drilling and recent field surveys were used to bring out the lateral and vertical disposition of the aquifer system. The study reveals the existence of multilayered aquifer system with four aquifer units (Aquifer I -Phreatic aquifer; Aquifer II – Leaky/confined aquifer; Aquifer-III & IV -Two Confined aquifers) upto the depth of 300m bgl. The determined disposition of the aquifer system is used for effective management of ground water aquifers in the Gadilam and Paravanar watershed.